The areas covered in the proposed work are as follows: 1) Study of the synthesis of ppGpp by ribosomes of HeLa cells which have been subjected to various forms of nutritional stress such as amino acid deprivation. Correlation of this effect with control mechanisms of eucaryote cells for regulation of the synthesis of stable forms of RNA. 2) Further purification and characterization of complexes of translational elongation factors 1 and 2 and aminoacyl tRNA synthetases. Determination of the biological significance of such complexes. 3) Further chemical and morphological characterization of particles which seem possibly associated with above complexes and which exist both intra- and extracellularly.